Vbulletin DownloadsII Product Modification

We need to modify a product DownloadsII for Vbulletin 4.0.3 Suite. We are building an upload-download system. The product already offers uploads/downloads, comments on files, categories. Adding new fields for file submissions, create custom content based on some form(template), linking this files to this custom content of Vbulletin 4.0.3 CMS is the main features we need.

ONLY Experienced with VBulletin 4 programmers needed! People that know what they are doing.